1. Field of the Invention
The present invention relates to a superimposing indicator in which photographing information is superimposed and indicated on an object image within a finder in a single lens reflex camera.
2. Description of Related Art
In known superimposing indicators, a mirror that partially functions as a half mirror is provided to project photographing information onto a focusing plate through a lower portion of the half mirror, or a mirror is provided to reflect the photographing information to project the same onto the focusing plate. However, in the former arrangement in which the mirror is partly provided with a half mirror, not only is the half mirror expensive, but also there is an irregular distribution of the quantity of light to be received in the finder. In the latter arrangement in which the reflection of light by the mirror towards the focusing plate occurs, as disclosed, for example in U.S. Pat. No. 4,949,118, it is necessary to relatively incline an image projecting lens and an information chart at a predetermined inclination angle, based on the Scheimpflug's Law. However, it is difficult to easily and correctly adjust the inclination angle. Furthermore, since light is made incident upon the focusing plate in an inclined manner, it is necessary to provide, for example, a small prism or the like on the focusing plate to thereby obtain a clear image of the photographing information.
It is an object of the present invention to provide a simple indicator within a finder, which can be applied to an existing single lens reflex camera without a substantial modification thereof.
Another object of the present invention is to provide a simple indicator for a single lens reflex camera having a picture image area (i.e., picture plane) size switching mechanism which switches a picture image area size between a standard size (i.e., 35 mm size) and an elongated size (i.e., panoramic size), wherein the selection of a panoramic mode can be easily indicated.